Search results for "figuration"
showing 10 items of 615 documents
A case of unusual anatomy: a maxillary lateral incisor with three canals.
1999
Case report A case of an unusual maxillary lateral incisor with three root canals is presented. The patient presented with localized swelling and a sinus tract. Because of its abnormal anatomical configuration, the tooth presented diagnostic and procedural difficulties. Conventional root canal treatment was performed successfully.
Introducing sustainability into university curricula: an indicator and baseline survey of the views of university teachers at the University of Valen…
2011
Many higher education institutions have assumed the role of diffusing knowledge, values, attitudes and behaviours that favour sustainability. A key objective in such work is training university teachers to apply sustainability criteria to their respective disciplines. While university teachers' active participation is essential to achieving this goal, their ideas about and predispositions towards introducing sustainability into curricula are not always understood or appreciated. In this paper, we report on a questionnaire survey at the University of Valencia, Spain, on the current baseline situation for introducing sustainability across the university's curricula. We also report on a measur…
Structure-Guided, Single-Point Modifications in the Phosphinic Dipeptide Structure Yield Highly Potent and Selective Inhibitors of Neutral Aminopepti…
2014
Seven crystal structures of alanyl aminopeptidase from Neisseria meningitides (the etiological agent of meningitis, NmAPN) complexed with organophosphorus compounds were resolved to determine the optimal inhibitor–enzyme interactions. The enantiomeric phosphonic acid analogs of Leu and hPhe, which correspond to the P1 amino acid residues of well-processed substrates, were used to assess the impact of the absolute configuration and the stereospecific hydrogen bond network formed between the aminophosphonate polar head and the active site residues on the binding affinity. For the hPhe analog, an imperfect stereochemical complementarity could be overcome by incorporating an appropriate P1 side…
X-Ray Crystallographic Analysis of the Charge-Density Wave Modulated Phases in the NbTe4-TaTe4 System
1999
NbTe4 and TaTe4 belong to the important structural family CuAl2 (tl20) characterized by a tetragonal antiprismatic coordination of the minority component. The basic structures were first described by Selte and Kjekshus [1] and Selte and Bjerkelund [2]. In these structures the Te atoms form 1-D infinite columns of stacked tetragonal antiprisms along [001] which are centered by the metal atoms (Figure 1). The arrangement of the antiprismatic columns in the tetragonal a 1 a 2-plane yields short Te-Te contacts, forming Te2 pairs with covalent bonds of about 2.92 A. Thus, following the usual chemical arguments MTe4 (M=Nb,Ta) is a ditelluride of M(IV), i.e. M4+(Te 2 2- )2. The structure is strong…
Automated segmentation and description of the internal morphology of human permanent teeth by means of micro-CT
2020
High-resolution micro-computed tomography is a powerful tool to analyze and visualize the internal morphology of human permanent teeth. It is increasingly used for investigation of epidemiological questions to provide the dentist with the necessary information required for successful endodontic treatment. The aim of the present paper was to propose an image processing method to automate parts of the work needed to fully describe the internal morphology of human permanent teeth. One hundred and four human teeth were scanned on a high-resolution micro-CT scanner using an automatic specimen changer. Python code in a Jupyter notebook was used to verify and process the scans, prepare the dataset…
Pieejas “Windows kā pakalpojums” izmantošana atjauninājumu instalēšanas automatizācijai organizācijas Windows operētājsistēmās
2020
Katru mēnesi tiek veikti operētājsistēmu uzlabojumi un izlaisti atjauninājumi. Tāpēc ir ļoti svarīgi nodrošināt, lai tehniskās ierīces būtu atjaunotas un tās saņemtu jaunākos drošības un funkcionalitātes labojumus, kas mazinātu operētājsistēmas darbības traucējumu rašanās risku. Darba mērķis ir veikt atjauninājumu instalēšanas automatizāciju organizācijas Windows operētājsistēmās izmantojot pieeju “Windows kā pakalpojums”. Darbā tika veikts vispārīgs pieejas “Windows kā pakalpojums” metožu apraksts un pielietotas pieejas metodes atjauninājumu automatizācijai, tādas kā Windows Server Update Services (WSUS) un Microsoft Endpoint Configuration Manager (MECM). Darba rezultātā ir veikta Windows …
Hybrid DFT calculations of the atomic and electronic structure for ABO3 perovskite (001) surfaces
2005
Abstract We present the results of first-principles calculations on two possible terminations of the (0 0 1) surfaces of SrTiO3, BaTiO3, and PbTiO3 perovskite crystals. Atomic structure and the electronic configurations were calculated for different 2D slabs, both stoichiometric and non-stoichiometric, using hybrid (B3PW) exchange-correlation technique and re-optimized basis sets of atomic (Gaussian) orbitals. Results are compared with previous calculations and available experimental data. The electronic density distribution near the surface and covalency effects are discussed in details for all three perovskites. Both SrTiO3 and BaTiO3 (0 0 1) surfaces demonstrate reduction of the optical …
Effect of the ΔPhe residue configuration on a didehydropeptides conformation: A combined CD and NMR study.
2010
Conformations of two pairs of dehydropeptides with the opposite configuration of the ΔPhe residue, Boc-Gly-Δ(Z)Phe-Gly-Phe-OMe (Z-OMe), Boc-Gly-Δ(E)Phe-Gly-Phe-OMe (E-OMe), Boc-Gly-Δ(Z)Phe-Gly-Phe-p-NA (Z-p-NA), and Boc-Gly-Δ(E)Phe-Gly-Phe-p-NA (E-p-NA) were compared on the basis of CD and NMR studies in MeOH, trifluoroethanol (TFE), MeCN, chloroform, and dimethylsulfoxide (DMSO). The CD results were used as the additional input data for the NMR-based determination of the detailed solution conformations of the peptides. It was found that E-OMe is unordered and Z-OMe, Z-p-NA, and E-p-NA adopt the β-turn conformation. There are two overlapping β-turns in each of those peptides: type II and ty…
A surprising switch in absolute configuration of anti-inflammatory macrolactones.
2016
Oxacyclododecindione-type macrolactones exhibit highly potent anti-inflammatory activities even at nanomolar concentration. After the determination of the relative configuration of the stereocenters at C14 and C15 by total synthesis of 4-dechloro-14-deoxyoxacyclododecindione and 14-deoxyoxacyclododecindione, the absolute configuration has now been assigned by X-ray crystallography. Surprisingly, the absolute configuration is (14S,15R) which differs for C15 from that of the well-known derivatives of (S)-curvularin. The biological activities of both enantiomers of 14-deoxyoxacyclododecindione, obtained by racemic synthesis and optical resolution, were investigated and the ring conformation of…
Synthesis of Pyrrolo[1,2-a]pyrimidine Enantiomers via Domino Ring-Closure followed by Retro Diels-Alder Protocol
2017
From 2-aminonorbornene hydroxamic acids, a simple and efficient method for the preparation of pyrrolo[1,2-a]pyrimidine enantiomers is reported. The synthesis is based on domino ring-closure followed by microwave-induced retro Diels-Alder (RDA) protocols, where the chirality of the desired products is transferred from norbornene derivatives. The stereochemistry of the synthesized compounds was proven by X-ray crystallography. The absolute configuration of the product is determined by the configuration of the starting amino hydroxamic acid. peerReviewed